Graphing Polynomial Fcn: y = x^3 + x^2 - 4x - 4

[Kyle]

Can someone please help me on graphing this function

y = x^3 + x^2 - 4x - 4

I know how to graph functions that are already factored out, but not one like this. Thank you

 

[Denis]

Can you not assign x values and get corresponding y's?

As example:
x = -4, y = -36
x = -3, y = -10
x = -2, y = 0
x = -1, y = 0
x = 0, y = -4
x = 1, y = -6
x = 2, y = 0
x = 3, y = 20
x = 4, y = 60

Go graph those; you'll get something like a radio wave...whatever

If you don't understand how to get the grapg points, back to class :shock:

 

[Mrspi]

Can someone please help me on graphing this function

y = x^3 + x^2 - 4x - 4

I know how to graph functions that are already factored out, but not one like this. Thank you

Since you "know how to graph functions that are already factored out," perhaps you should try to factor THIS one. Group the first two terms together and the last two terms together:

x<SUP>3</SUP> + x<SUP>2</SUP> - 4x - 4

The first two terms have a common factor of x<SUP>2</SUP> and the last two terms have a common factor of -4. Remove the common factor from each pair of terms:

x<SUP>2</SUP>(x + 1) - 4(x + 1)

Now, (x + 1) is a common factor. Removing it gives
(x + 1)(x<SUP>2</SUP> - 4)

You can factor that second binomial as a difference of two squares. Can you continue?

 

[Kyle]

@Denis- Yes I can, but I was looking for the method Mrspi used, thanks for the tip though I can use that to check my graph.

@Mrspi- thanks for the help, Looks like I come out with (x+1)(x-2)(x+2). Thanks for giving me the thought I needed to do this stuff. It helped me a lot.